/*
 * This file contains code from "C++ Primer, Fourth Edition", by Stanley B.
 * Lippman, Jose Lajoie, and Barbara E. Moo, and is covered under the
 * copyright and warranty notices given in that book:
 *
 * "Copyright (c) 2005 by Objectwrite, Inc., Jose Lajoie, and Barbara E. Moo."
 *
 *
 * "The authors and publisher have taken care in the preparation of this book,
 * but make no expressed or implied warranty of any kind and assume no
 * responsibility for errors or omissions. No liability is assumed for
 * incidental or consequential damages in connection with or arising out of the
 * use of the information or programs contained herein."
 *
 * Permission is granted for this code to be used for educational purposes in
 * association with the book, given proper citation if and when posted or
 * reproduced.Any commercial use of this code requires the explicit written
 * permission of the publisher, Addison-Wesley Professional, a division of
 * Pearson Education, Inc. Send your request for permission, stating clearly
 * what code you would like to use, and in what specific way, to the following
 * address:
 *
 *  Pearson Education, Inc.
 *  Rights and Contracts Department
 *  75 Arlington Street, Suite 300
 *  Boston, MA 02216
 *  Fax: (617) 848-7047
*/

#include <string>
#include <iostream>

class Screen
{
public:
	// interface member functions
	typedef std::string::size_type index;
	char get() const
	{
		return contents[cursor];
	}
	inline char get(index ht, index wd) const;
	Screen(index ht = 0, index wd = 0):
		contents(ht * wd, ' '), cursor(0), height(ht), width(wd) { }
	Screen& move(index r, index c);
	Screen& set(char);
	Screen& set(index, index, char);
	// display overloaded on whether the object is const or not
	Screen& display(std::ostream& os)
	{
		do_display(os);
		return *this;
	}
	const Screen& display(std::ostream& os) const
	{
		do_display(os);
		return *this;
	}
private:
	// single function to do the work of displaying a Screen,
	// will be called by the display operations
	void do_display(std::ostream& os) const
	{
		os << contents;
	}
	// as before
private:
	std::string contents;
	index cursor;
	index height, width;
	// other members as before
};

Screen& Screen::set(char c)
{
	contents[cursor] = c;
	return *this;
}

Screen& Screen::move(index r, index c)
{
	index row = r * width; // row location
	cursor = row + c;
	return *this;
}

Screen& Screen::set(index r, index c, char ch)
{
	index row = r * width; // row location
	contents[row + c] = ch;
	return *this;
}

char Screen::get(index r, index c) const
{
	index row = r * width; // row location
	return contents[row + c];
}

